Expandable polystyrene strand expander



Jan. 12, 1965 D. c. PAULSON 3,165,303

EXFANDABLE POLYSTYRENE STRAND EXPANDER Filed April 18, 1962 STEAM INVENTOR.

Joya [g sgjfcjiizz United States Patent r 3,165,303 EXPANDABLE POLYSTYRENE STRAND EXPANDER Donald C. Paulson, Midland, Mich., assignor to The This invention relates to an improvement in an expander for continuously foam expanding polystyrene strands.

Various devices have been proposed and utilized with varying degrees of success for continuous foam expansion of polystyrene strands. Two problems may arise, which are most diflicult to solve, namely, the feeding of the strands into a drum expander, and keeping the strands from sticking together. Feeding the strands into the drum by means of an aspirator is not generally satisfactory because of the non-uniform shape of the strands. Agitation of the strands in the drum could not be done successfully because of binding of the moving bars, which would stop rotation of the drum agitator.

The device of the present invention may be used to continuously foam expandable polystyrene strands in a highly efficient and completely satisfactory manner. Briefly, the device incorporates an auger feed mechanism which moves the strands into the bottom of a drum. Steam is injected into the drum and the foamed strands move upwardly and exit through an opening formed in an upper portion of the drum. Only two agitator bars are employed to prevent clumping of the strands, the arrangement of the bars being such as to prevent binding of the agitating means. It will be seen that the device of the invention represents an improvement in the art of expanders for continuously foam expanding polystyrene strands.

The main object of this invention is to provide an improvement in an expander for continuously foam expanding polystyrene strands.

A more specific object is to provide a polystyrene strand expander with an improved material feed or delivery means.

Another object is to provide a polystyrene strand expander wherein agitator means are provided which will prevent strand clumping without binding of the agitator.

Still another object of the invention is to provide a polystyrene strand expander which is of simplified and compact structure.

These and further objects and features of the invention will become more apparent from the following descrip tion and accompanying drawing wherein:

FIG. 1 is an elevation view, in partial section, showing a device embodying the principles of the invention; and

FIG. 2 is a section view generally as seen along line 22 in FIG. 1.

Referring now to the drawing, the numeral 8 identifies an enclosed cylindrical receptacle, or drum, which is formed to provide a material outlet opening 10 in a side region thereof. A shaft 12 is supported for rotary movement in the drum, the longitudinal axis of the shaft being arranged to coincide with the axis of the drum. A pair of axially spaced agitator rods or bars 14 and 16, are arranged to extend horizontally from the shaft, the ends of rod 14 being movable in the region of the opening 10, while bar 16 is arranged to be nearer the bottom of the drum. A stationary agitator rod or bar 18, is arranged to project radially inward in the drum in a region between I 4 3,165,33 Patented Jan. 12, 1965 "ice lower end thereof and extends upwardly at an angle. A

positive displacement strand feed means in the form of a helical feed screw, or auger 24, is arranged in the pipe 22, the upper end of the feed screw being connected to a universal joint 26 which is in driving connection with a g'ear'28-. The latter is positioned for meshing with a spur gear 30 which is mounted upon one end of a shaft 32, the other 'end of the shaft having asprocket wheel 34 secured thereto. A frame'means 35 is arranged for positionally maintaining the gears 28, 30 and associated parts. A drive chain 36 connects the sprocket 34 with a sprocket wheel 38 affixed to the end of the shaft 12. The latter has a second sprocket wheel 40 secured thereto for engagement by a drive chain 42 which is driven by a power means (not shown). In such manner, simultaneous rotation of the shaft 12 and the auger 24, is effected with the use of a common power driving means.

A feed bin, or hopper 44, is mounted for gravity feed supply of material into the feeder pipe 22 prior to its treatment. In addition auger 24 tends to agitate the strands in the hopper thus keeping them loose for entry into pipe 22. Afiixed near the lower end of the feeder pipe 22, and at an angle thereto, is a pipe 46, which is arranged to admit compressed air to the pipe 22, from a source not shown. This airs principal purpose is to create a fluid flow to keep the strands cool so as to prevent foaming thereof prior to their entry into drum 8. It is preferable that the air inlet be located near the bottom of pipe 22 to keep steam, discussed hereinafter, from entering the same. The air can also assist in conveying material from the pipe 22 into the drum.

The operation of the device is self-evident. Raw material, such as unexpanded polystyrene strands, are gravity fed from the hopper 44 into the feeder pipe 22, which strands are moved downwardly by action of the auger 24. When the strands enter the bottom of the drum 8, they are heated by steam injected into the bottom of the drum via the pipe 20. Upon heating a given amount, the strands are expanded and move upwardly in the drum by virtue of their lighter weight, and as assisted by upward movement of air from pipe 46. The rotating agitator bars 14 and 16 keep the expanded beads from clumping as they move upwardly in the drum and flow out of the opening 10. Means (not shown) are used to collect the expanded strands as they emerge from the opening 10.

It will be seen that a device made in accordance with the principles of the invention, will satisfy the objectives set forth hereinbefore. While the device has been described in connection with the expanding of polystyrene strands, it will be obvious that it may be used with equal effect for expanding other types of materials. The foregoing description has been given in detail Without thought of limitation since the inventive principles involved are capable of assuming other forms Without departing from the spirit of the invention or the scope of the following claims.

What is clamed is:

1. A device for expanding foam expandable polystyrene strands comprising in combination, a drum formed to provide an expanded strand outlet, a feeder pipe opening into the lower end of the drum, an anger positioned in the feed pipe, said auger rotatable to move strands into the drum, a pipe for admission of compressed air into the feed pipe at the lower end of the drum, a pipe arranged to inject steam into the lower end of the drum, and an agitator means positionedin the drum, said agitator means including arms arranged in spaced relation upon a rotatable shaft.

2. A device for expanding foam expandable polystyrene strands comprising in combination, a drum formed to provide an expanded strand outlet, a feeder pipe arranged at an angle with and openinginto the lower end l of the drum, an auger positioned in'the feed pipe, said auger rotatable to move strands-into the drum, a'ho'pper arranged for gravity feeding of unexpanded strands into the feeder pipe, a pipe for admission ofcompressed air into. the feederpipe at the lower end of the drum, a pipe arranged to inject'steam tangentially into the loweraend of the drum, and an agitator means including a vertically arranged shaft centrallypositioned in the drum and hav-.

ing a pair of horizontally arranged rods, one of which is in the region of the strand outlet the other of which is nearer the bottom of the drum.

7 3. A device according to claim 2, wherein a stationary agitator rod is afiixed to the drum and projecting radially inward? in a region between the two movable agitator rods. 4. A device'accordin'g to claim 2, wherein meansvare provided to simultaneouslyrotate the-agitator shaft and the auger from a single power source. H

References Cited in the file of this patent UNITED STATES PATENTS- l,499,850 Bonnard July'l, 1924 2,139,585 Hunter Dec. 6, 1938 2,522,936 Ferguson -Sept. 19, 1950 2,896,923 Luscombe a July 28, ,1959 3,023,175

Rodman nu Feb.' 27,1962 

1. A DEVICE FOR EXPANDING FOAM EXPANDABLE POLYSTYRENE STRANDS COMPRISING IN COMBINATIONS, A DRUM FORMED TO PROVIDE AN EXPANDED STRAND OUTLET, A FEEDER PIPE OPENING INTO THE LOWER END OF THE DRUM, AN AUGER POSITIONED IN THE FEED PIPE, SAID AUGER ROTATABLE TO MOVE STRANDS INTO THE DRUM, A PIPE FOR ADMISSION OF COMPRESSED AIR INTO THE FEED PIPE AT THE LOWER END OF THE DRUM, A PIPE ARRANGED TO INJECT STEAM INTO THE LOWER END OF THE DRUMAND AN AGITATOR MEANS POSITIONED IN THE DRUM, SAID AGITATOR MEANS INCLUDING ARMS ARRANGED IN SPACED RELATION UPON A ROTATABLE SHAFT. 